The Oakland Athletics, riding a six-game win streak, are threatening to shake up the American League West standings and wild-card race as they rise up the power rankings.

The A's, with a major league-best 33-10 record since June 16, are four games back of the Houston Astros in their division and 2 1/2 behind the New York Yankees for the top wild-card spot.

How have the A's, now ranked a season-high fifth in USA TODAY Sports' MLB power rankings, done it?

They have the fourth-best ERA (3.84) in the AL, an MLB-best 21-9 record in one-run games and are the only team with an unbeaten record when leading after the seventh (45-0) and eighth innings (53-0).

Meanwhile, the Astros are coping with several injuries, which could include All-Star outfielder George Springer, who exited Sunday's loss against the Los Angeles Dodgers after hurting his left thumb on a headfirst slide. Houston, which is 4-6 in its last 10 games, is already without second baseman Jose Altuve, shortstop Carlos Correa, catcher Brian McCann and pitchers Lance McCullers Jr. and Chris Devenski -- all of whom are on the disabled list.

A look at the voting from 1 to 30:

TEAM. MOVEMENT

1. Boston Red Sox (--)

►After four-game sweep, lead Yankees by 9 1/2 games in AL East, but play six more times in September.

2. Houston Astros (+1)

►Roberto Osuna gets second chance with defending champions.

3. New York Yankees (-1)

►Aaron Judge is still experiencing pain in his wrist and has yet to resume swinging a bat.